Domestic clothes dryers typically employ a cylindrical basket or drum mounted in a housing for rotation about its horizontal axis. At its front end, the drum is open to a port in the cabinet of the dryer which may be opened and closed by a hinged door. The drum is rotated, usually by an electric motor and belt drive, to tumble wet clothing that has been placed therein, and such tumbling action may be facilitated by one or more baffles circumferentially arranged about and fixed to the inside cylindrical wall of the drum. As the wet clothes are tumbled, heated air is passed through the drum to promote evaporation.
In some dryers, the entire periphery of the drum is perforated to allow heated air to directly enter the drum from an enclosed outer casing. In other dryers, a perforated inlet area may be at the front or rear end of the drum, and such drum revolves in a full or partial casing that has an inlet opening and an outlet opening either at opposite sides thereof or at the same side in spaced relation.
Domestic clothes dryers typically draw air from the room in which they are located and exhaust the moisture-laden air exiting the drum through a vent duct to the outside of the home. If the dryer is located in an air-conditioned or heated environment, a significant quantity of the preconditioned air would be lost during operation of the dryer and would require replacement by unconditioned air drawn from the outside. Another common practice has been to exhaust the moisture-laden air back into the room, particularly during the winter months, for heat reclamation and humidifying purposes, and many convenience devices have been provided for this purpose. This however may be undesirable for a number of reasons, one being the possibility of damage to or premature failure of various dryer components such as the electric motor and controls therefor due to the resultant high humidity in the dryer's immediate environment. In addition, the resultant recycling of moisture-laden air will lengthen the drying time in view of its lessened ability to extract moisture from wet clothing being dried.
In gas clothes dryers, the utilized burner is often of the single port type which directs the burner flame into a tube where the hot combustion products mix with dilution air. The thusly heated air is then drawn through and exhausted from the drum by a blower which may be driven by the same motor driving the drum. The temperature of the exhausted air is monitored by a thermostat which cycles a gas control valve between on and off positions indirectly to maintain the clothing temperature within a preselected safe range.
Most if not all dryers, whether gas or electric, employ a filter or lint trap to remove entrained lint from the air exiting the drum. From time to time, the filter must be removed and cleaned of trapped lint to ensure proper air flow and operation of the dryer. For obvious reasons, a clogged filter will adversely affect the dryer's performance and efficiency. Heretofore, it has been the responsibility of the operator to check the filter which may require removal of the filter for visual inspection. If the operator forgets, the dryer might then be operated at less than peak efficiency or possibly with damaging results.